1. Prior Art
Distributed energy resources, or DER, may include power generation capacity located at customer sites and/or located near load centers. This is sometimes referred to in the art as “distributed generation” to distinguish it from-central station generation, which is prevailing in the art.
It is increasingly understood in the art that reduction of demand upon command from the system operator, sometimes referred to as “dispatchable demand reduction” or load shedding, is in some respects an alternative to adding incremental generating capacity. The capacity, or energy source, represented by dispatchable demand reduction is, by definition, located at customer sites. Dispatchable demand reduction thus may be considered DER.
DER may also include the capacitors, reactive energy sources that provide reactive power capacity, and that are located at various points within either the transmission system or the distribution system as part of conventional practice in the art. It should be noted that in this description we use the term capacity with two meanings depending on context. Capacitors may have a certain capacity value or capicitance and energy sources provide added capacity to the network, either as real power, e.g., a generator, or reactive power, e.g., a capacitor bank.
The potential for distributed energy resources to augment traditional central-station power generation approaches is widely discussed within and outside the power industry. However, the prior art includes no methodology that thoroughly assesses and values the potential benefits of DER. Specifically, current methods fail to thoroughly assess and value the potential benefits of DER to transmission or distribution (T&D) systems themselves. Such benefits are to be considered distinct from potential benefits of DER to customers or the environment.
Making Connections: Case Studies of interconnection Barriers and their Impact on Distributed Generation Projects, Alderfer, Eldrige, and Stars, NREL/SR-20028053, May 2000, is one of many references in the art that acknowledges the potential for DER (in this case power generation at the energy customer's site) to provide benefits to customers. Such customer benefits may include increased reliability or reduced energy costs. Making Connections also acknowledges the potential for DER to provide benefits for the environment. These environmental benefits might include production of electric power at higher levels of efficiency (thus, reduced fuel use) or reduced environmental impacts through the use of advanced or renewable technologies.
However, Making Connections makes no reference to the potential for DER to provide benefits to T&D systems per se, over and above the potential benefits of DER for customers and the environment.
Where impacts of DER on T&D systems are considered, current methods do not provide a means to assess the potential benefits of DER to such T&D systems.
PIER Strategic Program—Strategic Distributed Energy Resources Research Assessment Interim Report, Arthur D. Little, P600-01-016, August 2001, considers grid impacts of DER at length. However, this report considers grid impacts of DER as a looming problem that may have to be dealt with if the level of penetration of DER is great enough. The report's literal characterization of the DER grid impacts issue is “Would a high penetration of DER have an adverse impact on the T&D system?” The report does not anticipate the affirmative use of DER as a means to improve performance of the T&D network.
Where DER is considered to have potential benefits for transmission and distribution systems, current methods fail to provide a thorough assessment and valuation of the potential benefits.
“The Energy Web,” by Steve Silberman, Wired Magazine, Sep. 7, 2001, describes an “Energy Web” with diversified resources close to customers managed by intelligent agents throughout the network. This infrastructure would have less environmental impact and provide more choices to customers. Silberman certainly implies that there could be grid benefits as well. However, Silberman offers no means for thoroughly determining what those benefits might be.
There is a need for a method to thoroughly assess and value the potential benefits of DER to transmission or distribution (T&D) systems themselves. Such a method should be analytically defensible. Also, such a method should quantify such benefits objectively, distinct from potential benefits of DER to customers or the environment.
The lack of an analytical basis for purported engineering and economic benefits of DER to T&D systems prevents sound business decision-making and policy-making that could facilitate the implementation of DER. If the potential T&D benefits of DER were objectively established, greater opportunities for the deployment of DER would emerge. DER projects could be deployed to provide direct benefits to customers, direct benefits to the environment, and also direct benefits to the T&D systems. With T&D benefits established independent of customer and environmental benefits, those projects that more than one set of benefits could be identified.
Regulations affecting industrial facilities and the practices relating to interconnection of devices to T&D systems have been developed over time, for the most part without anticipation or consideration of the possible widespread deployment of DER. These regulations and practices may now, without specific intent, represent barriers to DER projects. This topic is the primary focus of Making Connections. However, removal of barriers to broader deployment of DER is a daunting problem for regulatory authorities, network operators and DER practitioners. A clear demonstration of the benefits of DER to T&D systems would provide greater motivation for network operators and other stakeholders to engage in the reformation of these barriers. Also, a determination of which barriers have the greatest impact on the DER projects having the most potential benefits for the system would provide a basis for targeting these reformation efforts.
T&D system analysis and planning methods in the art have significant limitations in making a thorough assessment of the potential benefits of DER to a given T&D network.
Traditional transmission system analysis methods in the art do not directly consider the related distribution systems. As a result, traditional approaches prohibit direct assessment of the extent to which transmission level problems arise from problems in the distribution system. Moreover, traditional approaches thus also prohibit direct assessment of the extent to which transmission level problems that may arise from problems in the distribution system are best mitigated at the distribution level, e.g. with DER.
Likewise, as noted below, distribution system analysis methods in the art do not directly consider the transmission network. As a result, traditional distribution analysis approaches prohibit direct assessment of the extent to which distribution level problems arise from problems in the transmission system. Traditional approaches thus also prohibit direct assessment of the extent to which distribution level problems that may arise from problems in the transmission system are best mitigated at the distribution level.
Methods and analytical tools for characterizing the conditions of high-voltage transmission systems and identifying problems therein are well known in the art. Some of these methods and analytical tools are described in U.S. Pat No. 5,594,659 to Schleuter and U.S. Pat No. 5,796,628 to Chiang. A common class of analytical methods is referred to in the art as “power flow” techniques.
There have also been recent advances in these methods. Of particular interest are analytical tools that use analytical methods to determine optimal transmission network control variable settings to minimize losses or power costs, as well as tools that use analytical methods to identify locations for reactive capacity additions. Another area of recent interest is tools that analyze a system's proximity to voltage collapse, or its voltage stability security. Schleuter's Method for Performing a Voltage Stability Security Assessment for a Region of an Electric Power Transmission System is an example of recent voltage security analytics. Chiang's Dynamic Method for Preventing Voltage collapse in Electrical Power Systems is another. These are discussed further below.
Methods and analytical tools for characterizing the conditions of distribution systems and identifying problems therein are also well known in the art. Some of these tools also use power flow methods. These tools have been enhanced recently with the development of the capability to consider unbalanced three-phase flow. These tools are thus well-suited to perform detailed design of distribution feeders with DER.
However, distribution system analysis methods in the art consider distribution circuits or feeders individually rather than as part of a network. As a result, traditional approaches prohibit direct assessment of the extent to which problems arising on one distribution feeder may affect, or be caused by, or may be best remedied on other distribution feeders.
Thus, by treating transmission and distribution systems independently, and by treating distribution feeders individually, conventional methods in the art effectively prevent considering whether network deficiencies observed at the transmission level may be more effectively remedied by DER interconnected at distribution-level voltages. Thus, the prior art presents significant limitations to a thorough assessment of the potential benefits of DER to a given T&D network.
Traditional analysis and planning of either transmission or distribution systems typically considers only changes in transmission or distribution elements—e.g. new lines, or new transformers, or reconfigurations or new settings for control variables, or in some cases new reactive capacity additions—as the means to improve network performance.
Where non-wires alternatives are considered, a class of alternatives, i.e., dispatchable demand reduction, reactive capacity, or generation, may be considered alone. Traditional methods do not include consideration of these alternatives interchangeably to achieve a certain outcome. In addition, traditional methods do not consider the broad set of impacts such alternatives may have. In particular, DER is often seen as a way to gain incremental energy or capacity, but using DER to improve system stability or even reduce losses is often not considered.
Thus, conventional approaches in the art, by failing to consider a broad set of DER alternatives and broad set of factors impacted by DER, cannot provide a comprehensive assessment of the potential benefits of DER to T&D systems.
Conventional approaches prohibit direct assessment of the extent to which non-wires alternatives such as power generation embedded within the network or dispatchable demand reduction, particularly those placed in the distribution portion of the network, could be used improve overall network performance, such as stability or voltage security.
These approaches also prohibit direct assessment of the extent to which such non-wires alternatives, particularly those placed in the distribution portion of the network, could be used to augment, defer, or avoid conventional network additions, particularly in the transmission portion of the network.
Neither the Chiang method or the Schleuter method deal directly with the question of the extent to which problems in a transmission system are the result of problems in the associated distribution system. Also, neither deals directly with the question of whether mitigating problems close to their source in the distribution system may be more effective than mitigating them at the transmission level. Chiang's method is demonstrated using transmission-only datasets, consistent with conventional practice in the art. Even though Schleuter notes that voltage instability problems can arise in both distribution systems and in transmission systems, his method does not provide any means for taking into account voltage instability problems in the distribution system. In fact, Schleuter's method excludes those instability problems that arise in distribution systems from consideration. Schleuter's method focuses exclusively on transmission systems and mathematical models of transmission systems.
Neither Chiang's method or Schleuter's method anticipates consideration of instability problems in distribution systems in the analysis of instability problems in transmission system. Also, neither anticipates any analysis to assess the degree to which instability problems in the transmission system arise from or are exacerbated by instability problems in the distribution system. Also, neither anticipates consideration of the extent to which mitigation of instability problems in the distribution system could also mitigate instability problems in the transmission system.
Neither Chiang's method or Schleuter's method anticipates the analysis of transmission and distribution integrated together as a single network to assess and/or remedy instability problems in the network overall. Also, neither anticipates consideration of the relative merits of mitigating instability problems in the distribution system rather than (or in addition to) mitigating them in the transmission system.
Schleuter's method is a voltage stability assessment method only. It does not provide a means to determine whether additions of real or reactive capacity within the system analyzed could mitigate the problems identified and improve voltage stability and system security.
Chiang's method provides the means to make a stability assessment on a near-term look-ahead basis (specifically 25 minutes ahead) based on anticipated loads. The method provides “load margin measures” or measures of the system's ability to withstand deviations from forecast load and generation conditions based on forecast voltage profiles. The method also anticipates operating responses including the addition of power generating capacity or load sheds to maintain stability in those areas of the system identified by the method as becoming weak.
Chiang's method does consider operational responses to predicted voltage collapse conditions; however, this method is designed to guide operational responses given the short (25 minute) predictive window. These responses would presumably be limited to deployment of existing load shed, generation or reactive capacity opportunities. Chiang's method does not address the question of how generation, load sheds, and reactive capacity, considered as interchangeable alternatives, could be embedded anywhere in the network on a planning basis to achieve the greatest improvement in network performance. Given a method to determine those additions of real and reactive capacity throughout the T&D network that would achieve the greatest operational improvement, Chiang's method could be used to guide operation or dispatch of that embedded capacity.
U.S. Pat No. 5,422,561 to Williams, et. al., describes a control strategy for reactive power capacity (switchable capacitors) installed in a power circuit that serves customer loads to control both customer voltage and reactive power flow in the circuit. The objective of the strategy is to increase generator efficiency by reducing the reactive power generators must provide, and to reduce losses and improve throughput capability of the circuit.
U.S. Pat No. 5,760,492 to Kanoi et. al., describes a control strategy for real power capacity (distributed generation) installed on a distribution feeder. The objective of Kanoi's strategy is to operate distributed generation units on the feeder to achieve a certain operating condition on the feeder.
The Williams strategy is based on the premise, accepted in the art, that reactive capacity close to the customer load is more effective than reactive capacity provided by a remote power generation source. Kanoi notes that widely varying conditions in lower voltage-level distribution systems, particularly where distributed generation units are present, make it difficult to control power quality merely by controlling voltage and reactive power at the transmission level.
However, both the Williams and Kanoi control strategies focus on individual lines of a power system. In neither case are the lines in question considered as part of a larger network comprised of many similar and dissimilar lines. The Williams strategy considers the impact of switching capacitors in a line with multiple voltages, where those voltages could represent transmission and distribution levels. But it does not contemplate the impact of switching capacitors throughout the network on conditions throughout the network. The Kanoi strategy considers the impact of dispatching generating units in a distribution line on the conditions of that line, its associated step-down transformer and its associated transmission line. It does not contemplate the impact of dispatching distributed generation units embedded throughout the network on conditions throughout the network.
Thus, in a limited way, both the Williams strategy and the Kanoi strategy acknowledge that problems in a transmission system may be the result problems in the distribution system, or that problems in a transmission system may be best mitigated in the distribution system. However, because both strategies focus on individual lines, not the network, neither is capable of addressing the extent to which problems observed in the transmission system are the accumulation of problems in the distribution system. Further, neither is capable of assessing the extent to which problems observed at either the transmission or distribution level are best mitigated at the distribution level, e.g. using DER.
Both the Williams and Kanoi strategies are operational strategies. In the case of Williams, the strategy focuses on the switching of existing capacitors to achieve certain types of operational improvements on the circuit. In the case of Kanoi, the strategy focuses on dispatching of distributed generation to achieve certain types of operational conditions on the distribution line and at its associated step-down transformer. Neither strategy considers where on a planning basis reactive capacity (in the case of the Williams strategy) or real capacity (in the case of the Kanoi strategy) should be located to provide the greatest benefit for the line in question. Further, neither considers where reactive or real capacity, as the case may be, should be placed within a broader network to provide the greatest benefit for the network.
Both strategies are examples of the practice in the art of considering a single class of embedded capacity and a narrow set of performance criteria. In the case of Williams, reactive capacity is managed to increase generator efficiency, reduce losses, and improve throughput capability of the circuit in question. In the case of Kanoi, real capacity is managed to achieve a given set of conditions on the distribution line and at the step-down transformer, specifically voltage levels. The Williams strategy does not consider real capacity (load sheds) or real and reactive power together (embedded generation) as additional means to improve performance of the circuit. The Kanoi strategy does not consider reactive capacity (capacitors) or load sheds as additional means to improve performance. The Williams strategy does not consider the impacts of adding or removing reactive capacity on the stability or voltage security of the circuit. The Kanoi strategy considers voltage, but not reactive power requirements or reactive power flows.
Because both strategies focus on an individual line, neither can address the question of the extent to which problems observed in a transmission system are the result of problems observed in the associated distribution system.
Because both strategies are limited to a single line and a single class of capacity, neither can address the broader question of whether mitigating network problems close to their source in the distribution system may be a more effective means of mitigating problems observed at the transmission level.
Most importantly, neither strategy can address the question of how generation, load sheds, and reactive capacity, considered as interchangeable alternatives, could be embedded anywhere in the broad network to achieve the greatest improvement in network performance.
U.S. Pat No. 5,684,710 to Ehlers describes the remote control of loads, specifically the restoration of power following an outage and the detection of outages. Again, Ehler's method does not consider any impacts beyond the distribution system, and does not consider any management of loads alone or in concert with other forms of DER for the purpose of enhancing network performance.
U.S. Pat No. 5,414,640 to Seem describes dispatchable demand reduction as an element in a power system. However. Seem's method considers dispatchable demand reduction only as a means to reduce energy consumption, not to as a means to improve T&D network performance. His method does not envision taking into account impacts on the transmission system or the coordination of the installation or operation of demand reduction with power generation and/or reactive capacity in the power system.
U.S. Pat No. 4,208,593 to Sullivan describes controllable electrical demand (or dispatchable demand management) in the art as selective disconnection of loads at specified levels of aggregate load. Sullivan describes a method and system for controlling electrical demand that overcomes disadvantages in the prior art arising from failures of the control system. Sullivan's method also introduces the capability to control demand on the basis of time as well as aggregate load. Again, Sullivan's method does not anticipate the use of dispatchable demand reduction as a way to improve network performance.
U.S. Pat No. 5,278,772 to Knupp describes a method for determining the operating profile, or dispatch, of multiple power generation units in a power system. However, under Knupp's method power generation units are dispatched based on their operating costs only. No consideration is given to the impact the operation of these units may have on network performance, and the dispatch of these units to improve network performance is not anticipated.
In Integrated Assessment of Dispersed Energy Resource Deployment (C. Marnay, R. Blanco, K. S. Hamachi, C. P. Kawaan, J. C. Osbom, F. J. Rubio, LBNL-46082, June 2000), the authors looked at the impacts of DER on the power system. However, the bulk of their study focused on the customer drivers for DER in an effort to develop a way to predict customer adoption. The implication is that DER adoption decisions are made by customers on their own without any knowledge or acknowledgement of the impacts on the grid. These customer decisions are thus something for the network operator to guess at and react to, hence the value of a predictive model. The study does not anticipate an assessment by the network operator of the types of DER projects that enhance network performance and/or the development of incentives to actively encourage such projects.
The study acknowledges that the “optimal” penetration of DER will require improved economic signals from the network operator to the customers, and states the need to compute such signals, but goes no further.
While the study acknowledged that distributed generation on a distribution feeder can have impacts at the transmission level, no attempt was made to evaluate the impacts of DER implemented at the distribution level on the transmission level, or to assess the potential for improving network performance through interactions between feeders.
Two generator additions were simulated on a single distribution feeder, analyzed as an isolated facility. The results showed that these additions could reduce losses and correct instances of overvoltage and undervoltage.
This analysis considered the distribution feeder as a standalone facility; it did not consider or anticipate a method or approach where the distribution feeder was incorporated with other feeders and transmission facilities in a larger network. This study's approach therefore could not consider how these additions could affect conditions at the transmission level or elsewhere in the network, nor could it directly assess the merits of capacity additions on the feeder vs. capacity additions at the transmission level or elsewhere in the network.
This work was performed as a demonstration of a particular software package's suitability for such analysis, not as a demonstration of a methodology to assess the potential for a variety of DER devices (generation, dispatchable load sheds, and capacitors) to achieve an overall improvement in power quality and losses in an integrated T&D network.
In Applications Guide: Distribution Capacity Planning With Distributed Resources, EPRI, TR-11468, January, 2000, EPRI characterizes the conventional assessment of DER benefits as the cost of a planned network upgrade that is avoided or deferred by DER capacity, less the cost of that DER capacity. EPRI points out that the limitation of this approach is that the “planned” network upgrade to be avoided or deferred was identified without consideration of DER in the plan.
The Area Investment Strategy Model developed by EPRI for assessing the benefits of DER involves analysis to determine if DER can be incorporated in distribution to minimize the overall cost of capacity required to serve customers. Again, this method focuses the distribution system alone. It also considers DER as a source of incremental capacity only; it does not consider DER as a means to improve system stability or voltage security.
A further limitation of such an approach is that the utility is not the decision-maker for DER projects sponsored by a customer or third party. Moreover, a utility cannot make an informed economic evaluation of customer-sponsored DER projects. The utility cannot determine the value the customer places on the project's customer benefits, particularly as these benefits may include such intangibles as energy cost certainty, independence, or peace of mind. The utility also cannot know the actual DER technology costs the customer has been quoted. Thus, a conclusion under the EPRI methodology that DER additions result in a least cost solution is at best incomplete, and might be incorrect. The EPRI method is not capable of assessing or quantifying the stand-alone benefits of DER to the T&D system.
A thorough assessment of the network benefits of DER requires an evaluation that goes beyond a distribution planning area by itself, or, for that matter, beyond the transmission system by itself. It also requires the consideration of a broad set of factors that DER may affect. A more efficient approach to DER planning is for the utility to determine the potential benefits DER could provide to the utility's system as described, and the nature of projects that would deliver those benefits, independently of customer considerations. Then the utility has the means to promote projects having similar characteristics among its customers (and discourage dissimilar projects). The utility then also has the ability to identify those projects that customers will not pursue but whose value to the system justifies utility investment.
In conclusion, we are aware of no method in the prior art of analyzing T&D networks that provides a thorough, objective assessment of the potential benefits DER may provide to a T&D network. This is due in part to the apparent absence of methods in the prior art that provide a means to directly observe the extent to which problems at the transmission level are caused by or exacerbated by problems at the distribution level (and vice versa). Among other things, this prevents the direct observation of the merit of remedying problems throughout the network close to where they occur, particularly at the distribution level, such as with DER.
The absence of a method that provides a thorough, objective assessment of the potential benefits of DER is also due in part to the apparent absence of methods in the prior art that simultaneously consider a variety of potential DER additions or that appropriately consider the range of impacts of DER.
The absence of a method that provides a thorough, objective assessment of the potential network benefits of DER is also due in part to the apparent absence of methods in the prior art that consider the potential network benefits of DER independently of the other potential benefits of DER.
We are also not aware of any method in the prior art that identifies a specific, theoretical set of DER projects that will improve or maximize performance of the subject T&D network. Further, we are aware of no method that identifies such projects for the purpose of guiding policies, identifying consequential barriers to beneficial projects, or designing DER incentives that share value rather than shift costs to non-participants.
Accordingly, one object of the present invention is to provide a method for providing a thorough assessment of the potential benefits DER may provide to a T&D network. Such benefits may include performance improvement such as the reduction in electrical losses, improvement in system stability and/or power quality. These benefits could also include the deferral or avoidance of system additions that would otherwise be required to reliably serve load.
A further object of the present invention is to provide a method for providing a thorough assessment of the potential benefits DER may provide to a T&D network that considers a variety of DER alternatives interchangeably, not generation, capacitors, or load sheds alone.
This object and the prior object overcome a significant drawback of the prior art in thoroughly assessing the potential T&D benefits of DER that arises from the practice of considering classes of DER individually and/or considering a narrow set of performance measures.
A further object of the present invention is to provide a method for analyzing the T&D network, including but not limited to providing a thorough and objective assessment of the potential benefits DER may provide to a T&D network, that includes a means to directly observe the extent to which problems at the transmission level are caused by or exacerbated by problems on any given distribution feeder (and vice versa).
A further object of the present invention is to provide a method for analyzing the T&D network, including but not limited to providing a thorough, objective assessment of the potential benefits DER may provide to a T&D network, that includes a means to directly consider the merits of remedying problems close to where they occur, whether in the distribution system or in the transmission system, including possibly using DER to remedy problems anywhere in the network.
This object and the prior object overcome a significant drawback in the prior art, particularly as it relates to assessing the benefits of DER to a T&D network, that arises from the analysis of transmission independently of distribution, and vice-versa, and the analysis of distribution feeders individually.
A further object of the present invention is to provide a method for analyzing the T&D network, including the incorporation of DER within the network, that facilitates the evaluation of how these elements should operate and interact under a variety of network conditions.
A further object of the present invention is to provide a method for providing an objective measure of the potential benefits DER may provide to a T&D network, where such measure is independent of non-network considerations such as DER benefits for customers or the environment.
This object enables decision-making relative to T&D network matters, including the design of DER incentives based on network benefits, without the distortion of non-network considerations.
A further object of the present invention is to provide a method for quantifying the potential benefits DER could provide a given network, in both engineering and economic or financial terms.
Quantifying potential T&D network benefits of DER in economic terms enables the transfer of the value associated with such network benefits between stakeholders. This could include, for example, financial incentives for DER projects based on a sharing of the network value such projects create rather than simply shifting costs from one set of customers to another.
A further object of the present invention is to provide a method for characterizing the specific DER projects that realize or approach the potential benefits DER may provide to a T&D network. This characterization would include where within the network particular types of DER would make the greatest contribution.
A thorough, objective assessment of the potential benefits of DER to a T&D network along with knowledge of the nature of projects that achieve those benefits would be of significant economic value to T&D network operators, generally utilities. Such information may reveal the potential for substantial savings in losses, improvements in power quality and/or stability, or the opportunity to defer or avoid costly network improvements.
Such an assessment of potential DER benefits, and the specific projects that would provide them, is of great value to a utility if determined objectively, independent of non-network considerations. A utility cannot accurately incorporate customer economics in its planning, nor can it unilaterally implement purported “least cost” solutions if they include customer-sponsored projects. Using the method of this invention a utility can quantify the potential benefits of DER for its system, and devise incentives that share that value with third parties to encourage beneficial DER projects and capture at least a portion of that potential value.
An objective assessment of the potential benefits of DER to a T&D network and knowledge of the nature of projects that achieve those benefits would permit the identification of those barriers that have the greatest impact on the DER projects with the greatest potential T&D benefit. This knowledge in turn would permit the development of high-impact, targeted policy initiatives to promote beneficial DER.
The method of this invention also has substantial economic value to developers of DER projects and vendors of DER technologies. By identifying an additional set of benefits, an additional beneficiary, and/or additional revenue sources for DER projects, and by facilitating policies that remove barriers to DER projects, this invention opens new markets for DER projects and DER technologies.
The means to analyze the integrated T&D network, with DER incorporated within the network, under a variety of conditions, would have great value to network operators and other stakeholders. The means to analyze the integrated T&D network, with DER incorporated within the network, under a variety of conditions, would permit, for example, identification of DER projects that make the greatest contribution to load-carrying capability of the overall network under peak load conditions, and an operating plan for those projects to provide other benefits under non-peak load conditions. This type of analysis is essential to realizing the potential of such concepts as those described in the Wired Magazine article above.
A method for analyzing the T&D network, including providing an objective assessment of the potential benefits DER may provide to a T&D network, that includes a means to directly observe the extent to which problems at the transmission level are caused by or exacerbated by problems on any given distribution feeder (and vice versa) would have substantial value to network operators by identifying the root causes of problems contributing to substandard network performance.
A method for analyzing the T&D network, including providing an objective assessment of the potential benefits DER may provide to a T&D network, that includes a means to directly consider the merits of remedying problems, where such problems may arise either at the transmission level or at the distribution level, at either the transmission level or at the distribution level would have substantial value to network operators in identifying additional solutions for remedying network problems, solutions that may be more effective and/or less costly to implement.
Such methods also have substantial economic value to developers of DER projects and vendors of DER technologies. An expansion of the understanding of the areas where DER projects may represent potential solutions to network problems would open new markets for DER projects and technologies.
Further objects and advantages of this invention will become apparent from consideration of the drawings and ensuing description.